mechanical temp gauge into 3800Sc ? (Page 1/2)
Lou6t4gto MAY 26, 03:35 PM
Wanting to install a Mechanical Temp Gauge into a 2000 3800SC in a 86 fiero. Isn't there ONLY 1 hole for a temp sender in a 3800 ? and doesn't the ECM have to use THAT elec temp Sender ??? How to do ? Thanks
Lou6t4gto MAY 26, 03:39 PM
CAN the stock elec temp "SENDER" supply info to the ECM, the stock gauge, AND an aftermarket temp gauge ??? do not totally TRUST the stock fiero gauge. most of the time it stays at 180, sometimes goes to 220. shut off the key , turn it back on and it goes back to 180 !

[This message has been edited by Lou6t4gto (edited 05-26-2020).]

Lou6t4gto MAY 27, 07:29 PM
any reason I cannot Thread a "T" Fitting into the stock hole and have the stock sender AND a Mech gauge ? I mean, "Physically I can do it, is there any" reason" it's a bad idea ??? LOL
Spoon MAY 27, 11:34 PM

quote
Originally posted by Lou6t4gto:

any reason I cannot Thread a "T" Fitting into the stock hole and have the stock sender AND a Mech gauge ? I mean, "Physically I can do it, is there any" reason" it's a bad idea ??? LOL



Seems like you figured it out with the tee. I did a similar thing on my 3800SC with the oil pressure sensor. I needed a way to shut down the electric power steering system until the engine was up and running.

spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

theogre MAY 28, 12:20 AM
ECT for ECM should In the Engine. Not T's etc to anything else.
That can mess up reading by ECM in turn mess up everything else.

Other temp senders don't like T'd either but most errors w/ them T'd won't matter much. Like Dash temp gauge w/ numbers often are way off to start w/ OE setup.

Coolant T's can trap air and slow δT or affect Total Temp even w/o trapped air.
If you must T, must minimize trapped air so Sender/Sensor Tip has coolant On them all of the time.

Best is find a plug coolant port/drain in the block or head to install you new gauge.

These are not like OP whatever when T'd. Pressure doesn't care about size or shape of a part or line. Doesn't care about trapped air too. Air compress = oil etc pressure and sender/switches still work normal.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

OntarioKev MAY 28, 12:50 AM
Just use a gauge that connects to OBD2 and reads the temp that way.

Aeroforce Interceptor is one such gauge, and it can display a lot more than temperature. No messing around with Ts or possibly getting incorrect readings.
darbysan MAY 28, 11:04 AM

quote
Originally posted by OntarioKev:

Just use a gauge that connects to OBD2 and reads the temp that way.

Aeroforce Interceptor is one such gauge, and it can display a lot more than temperature. No messing around with Ts or possibly getting incorrect readings.



I was just going to suggest the same thing. I have used the Autool X60 gauge in two of my builds. Not only do you get extra info, but you also can do things like clear codes, etc.

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'87 GT , '00 3800 Series II SC, 4t65e, Vue Power Steering. (SOLD)

Lou6t4gto MAY 28, 06:23 PM
think I'm going to put an inline "sleeve"( with a threaded hole) in the cooling hose coming off the thermostat neck. I know it won't Register until the thermostat opens, but thats ok too.
Spoon JUN 02, 07:32 PM

quote
Originally posted by Lou6t4gto:

think I'm going to put an inline "sleeve"( with a threaded hole) in the cooling hose coming off the thermostat neck. I know it won't Register until the thermostat opens, but thats ok too.



What about "if it opens?" Just saying............

Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

cmechmann JUN 02, 10:36 PM
You may already know this.
I'm using the 3 wire ECT sensor used on grand prix 3800 with gauge package. The sensor is a coolant sensor and temp sending unit in one. Using the stock gauge, it has been working very well. It goes without saying if the meter assembly is buggy, it won't read properly. In the years I've been working on cars, I have not had one of the sensor/sending units fail.
Due to me using an older 1993 PCM that used Quad driver error codes, I had to hook up a light to the PCM output for temperature light to keep it from throwing an error code. I used the shift light circuit in the instrument panel as a substitute.
However if you still feel that this is not trusting enough. Use the sensor/sending unit for the PCM/ECM and stock gauge. I would use the LIM coolant port for the heater hose. To Tee in the mechanical gauge. If I am not mistaken, the timing cover heater port is return to the pump. That way you will get readings before the thermostat opens or not. On my set up I had used the 3800 thermostat housing. I removed the bleeder and installed a small hose fitting and overflow bottle from Cobalt/Ion 2.2 Ecotech so the system is self bleeding. The return of the overflow bottle is Tee'd to the return heater hose.

[This message has been edited by cmechmann (edited 06-02-2020).]